1. Field of the Invention
The present invention relates to an electronic rubbed-string instrument and, more particularly, to an electronic rubbed-string instrument, such as a violin, a viola and a cello, which generates desired musical tones in response to rubbing operations or bowing operations performed by a player.
2. Description of the Related Art
In the field of electronic rubbed-string instruments, electronic musical instruments are well known in which rotary rods corresponding to strings and each provided at its one end with a generator are rotated in response to bowing operations, and musical tones having sound volume corresponding to the rotational speeds of the rod are generated. For example, an electronic musical instrument of this kind is described in Japanese Utility Model Kokai Sho 55-32849.
In the conventional electronic rubbed-string instruments, when a speed of a bow movement is increased and an analog bowing detection signal (output voltage) is gradually increased in response to the above speed, the sound volume of a musical tone can be gradually increased in proportion to the above signal increase.
However, in the above conventional electronic rubbed-string instruments, it is only possible to proportionally increase or decrease the sound volume of the musical tone, but, for example, when a bow is moved gradually fast, it is not possible to decrease the sound volume of the musical tone in inverse proportion to the bow-movement speed. The above conventional musical instruments have other drawback that when the bow-movement speed exceeds a predetermined level, it is impossible to rapidly increase the sound volume from a certain volume level. In addition, they have a further drawback that not only the sound volume of a musical tone to be generated but also its other musical characteristics such as tone color characteristic and pitch characteristic can not be appropriately changed.
The generators used in the above conventional electronic rubbed-string instruments do not respond well to the bow operation performed by the player. Therefore, for example, when the player operates the bow abruptly fast from the beginning, the generator does not rapidly raise the output level. For this reason, it is impossible in these musical instruments to generate from the beginning a musical tone having a large sound volume and also having an attack at the time of the commencement of a performance. As described above, the conventional electronic rubbed-string instruments have a drawback that in the instruments the bow operation performed by the player does not appropriately affect the sound volume of a musical tone to be generated. On the contrary to the above mentioned case, it may be proposed to use a generator having a fine and high responsibility. But if the generator having a high responsibility is employed in the musical instrument, the musical instrument will have another drawback that it generates an accidental and unnecessary tone, even when the bow is simply put on the strings for a bowing operation or when a wrong operation happens.
In a violin as one type of typical acoustic rubbed-string instruments, tone color of a musical tone to be generated is appropriately controlled by adjustment of the pressure applied to a string by use of a bow (bowing pressure). Meanwhile, in the above electronic rubbed-string instruments, it is impossible to change tone color of a musical tone to be generated by the adjustment of the bowing pressure. Therefore, in order to provide a performance similar to that given by typical acoustic rubbed-string instruments, the above electronic rubbed-string instruments are still imperfect in functions. Recently, an electronic rubbed-string instrument has been developed in which a bowing pressure detection sensor for detecting pressure applied to strings by use of a bow is provided on the bow adapted to be drawn across the strings. This electronic rubbed-string instrument is disclosed in U.S. Pat. No. 4,805,510.
However, when a musician plays the above electronic rubbed-string instrument, he has to use the bow which is provided with the bowing pressure detection sensor in order to detect the bow pressure applied to the strings. Accordingly, the musician can not use a rod-shaped bowing member instead of the bow adapted to be used with the typical violin and the like and a substitute for the bow, when he plays the above electronic rubbed-string instrument. Therefore, there is a disadvantage that the electronic rubbed-string instrument can not be played without any restriction. As described in U.S. Pat. No. 4,805,510, in the electronic rubbed-string instrument, a pressure signal detected by the bowing pressure detection section is only supplied to a frequency synthesizer, so that the tone color of a musical tone to be generated can not be controlled on the basis of the above pressure signal. Therefore, there is a disadvantage that with use of the above electronic rubbed-string instrument, effect similar to that provided by playing the typical acoustic rubbed-string instrument can not be obtained.
In the typical acoustic rubbed-string instrument such as a violin, characteristics of a musical tone to be generated can be changed in accordance with the bowing directions. For example, since the bowing speed and the bowing pressure applied to strings are different between when the bow is drawn across the strings in one direction and when the bow is drawn in the counter direction, sound volume characteristics of the musical tone to be generated are different.
However, the conventional electronic rubbed-string instruments have a drawback that characteristics of a musical tone to be generated can not be made different in accordance with the bowing directions.
Further, in the typical acoustic rubbed string instrument such as a violin, tone color characteristics of a musical tone to be generated are made different in accordance with contacting positions where an expanded string is touched with the bow. For example, when the bow is drawn across the strings nearby a fingerboard, a musical tone having soft tone color is generated and on the contrary, when the bow is drawn across the strings nearby a bridge, a musical tone having hard tone color is generated.
However, the conventional electronic rubbed-string instruments have a drawback that the tone color of the musical tone can not be changed in accordance with contact positions where the string is touched with the bow.